figured I'd post the solution here in case anyone stumbles across the same problem.
K2 requires multi-byte string array functions to be enabled.
hot to check.
look for extension=php_mbstring.dll (windows IIS) in your php.ini file, or (most users) can login to their admin panel click 'Help' menu > 'System Info' then the 'PHP Settings' tab and look for mbstring enabled at the bottom, should be yes.
If no, in windows IIS, click add remove programs, find php install, clikc change, find 'Multi Byte String Functions' option under extensions next next finish etc... and then restart computer to restart php, or to restart php without restarting computer follow below instructions.
NOTE: first you must make sure that the following line appears in your php.ini file near the bottom:
extension=php_mbstring.dll
to restart php:
Open Services (run services.msc)
Find SMTP (think its listed as 'Simple Mail Transfer Protocol (SMTP)' right click and click stop
Find 'World Wide Web Publishing Service', right click and click stop
Find 'IIS Admin Service' right-click and click restart... when it asks if you want to restart the dependant or other services, click yes... wait for it to restart all services and then continue below.
Find 'World Wibe Web PUblishing Service' again and right click and click start
Find 'SMTP' again, right click and click start...
now check for mbstring enabled: yes shows properly in your backend and k2 should now work.
enjoy.